Karen drove the military ambulance across the river and once on the bridge marveled over the fact that only two vehicles seemed to have been abandoned on it's span. This was different from other river crossings she'd made and often found blocked by vehicles that had been abandoned in the panic. 

She was happy with her discovery so she hummed a cheerful tune to herself as she drove along.

Karen was a little nervous about being alone in a world populated by the moving dead and wandering bands of feral humans but riding in the up armored Humvee gave her some security. She liked being safe but she also liked to help people which was why she became a doctor 

She drove no faster than 30 mph knowing that any faster and she would stand a chance of getting trapped in a cul-de-sac. The Hummer was a powerful machine but even it had it's limits she'd learned and with the lighting tower even more so.